Ag groups bracing for cancer classification on 2,4-D herbicide

WASHINGTON, June 10, 2015 – The International Agency for Cancer Research (IARC), an arm of World Health Organization that classified the herbicide glyphosate as a “probable carcinogen,” recently met to review another widely used herbicide, 2,4-D, and the agricultural industry is bracing for similar results to be released later this month.

The National Corn Growers Association and the American Soybean Association expect the IARC to also classify 2,4-D as “probably carcinogenic,” a designation that “will only lead to more confusion and concern,” the groups said last week in a joint statement.

They also noted that following the IARC report, “activists called for EPA to consider immediately pulling glyphosate from the market despite an overwhelming response from scientists acknowledging the safety of the product. We’re concerned the same thing may happen again this month when IARC is going to release the findings of its review of several more substances, including 2,4-D, dicamba and other crop protection tools.”

In March, IARC categorized glyphosate - an herbicide used on millions of acres of commodity crops in the U.S. - as a Group 2A agent, “probably carcinogenic to humans.” Group 2A is one rank higher than IARC's Group 2B, which indicates an agent is “possibly carcinogenic to humans,” and includes cell phones and coffee. Group 1 is the next highest category and denotes an agent is a known carcinogen.

The EPA last year approved a new use for 2,4-D -- a chemical in use since the 1940s -- in a Dow AgroSciences product called Enlist Duo, a mixture of glyphosate and 2,4-D. The agency approved Enlist Duo for commercial use in 15 states.

The Environmental Working Group, along with other environmental groups, filed a lawsuit against EPA for its approval of the product. EWG also asked EPA to “heavily weigh” IARC’s glyphosate classification in the agency’s upcoming review of the chemical. (EPA is supposed to review each registered pesticide every 15 years to determine whether it continues to meet standards set by federal law.)

When EPA evaluated Enlist Duo it concluded that the herbicide meets safety standards for the public, agricultural workers and endangered species. The product contains what EPA described as a “new, lower volatility pesticide formulation” that uses the choline salt of 2,4-D.

“This action will provide an additional tool to reduce the spread of glyphosate-resistant weeds,” EPA noted. The agency included stewardship requirements for Dow AgroSciences in its terms of approval.

However, Mary Ellen Kustin, EWG senior policy analyst, said in an interview with Agri-Pulse that EPA’s analysis of Enlist Duo didn’t properly evaluate how 2,4-D and glyphosate would react together—although they are both separately considered safe by the agency. Also, Kustin said the agency focuses on what “should happen” if pesticides are used according to regulation, but “unfortunately EPA doesn’t account for all real world variables.”

Kustin pointed to studies that she says convey a link between 2,4-D exposure and cancer, including the National Institutes of Health Agricultural Health Study , which focused on research that evaluated more than 20 pesticides to determine whether the farmers who use them have increased risks of developing cancer. Kustin also highlighted a study by two IARC scientists that associated farm workers’ exposure to 2,4-D with a 40 percent higher risk of Non-Hodgkin lymphoma.

However, according to the 2,4-D Task Force, made up of Dow AgroSciences, Agro-Gor Corp. and Nufarm Ltd. of Australia, all of the studies that IARC will consider in its review have previously been reviewed by the EPA and other health and safety regulators around the world.

“IARC ranks things based on their potential hazard, but one must look at how something is used in order to assess the real-world risk,” the task force explained in a media statement. “For example, IARC classifies coffee as a carcinogen, but you would have to drink about 50 cups per day every day for 50 years to consume the amount of coffee necessary to cause reason for concern.”

The task force notes that 2,4-D has been assessed multiple times for health and safety by regulators around the world, including the EPA, and they continue to conclude that 2,4-D can be used safely according to label directions. “There is widespread agreement among health and safety regulators in 89 countries…not one health and safety regulator in the world considers 2,4-D to be a carcinogen,” the task force stated.

Also, IARC is not tasked with regulating pesticides and other chemicals, according to the task force. The body responsible for conducting risk assessments of pesticides for regulatory purposes is the Joint FAO/WHO Meeting on Pesticide Residues, administered by the Food and Agriculture Organization of the United Nations and the World Health Organization.

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The world of agriculture extends beyond what’s growing in your field or living in your barn, and here at Agri-Pulse, we understand that. We make it our duty to inform you of the most up-to-date agricultural and rural policy decisions being made in Washington D.C. and examine how they will affect you – the farmer, the lobbyist, the government employee, the educator, the consultant and the concerned citizen.